This invention relates in general to shipping containers used to transport flowable dry bulk goods. In order to economically transport dry bulk goods, it is necessary to use a sufficiently large container that can be transported by a variety of means, including by truck, sea or rail, and the container must be easily loaded and unloaded using commonly available apparatus. It is known in the art to use hoppers, tanks and similar containers for transporting both dry goods and liquid product. However, such known containers suffer from design flaws which make them difficult and/or uneconomical to use. Specifically, the dry goods containers presently on the market require that the container be tipped to unload the product. Such a design is undesirable because of the problems inherent in tipping such a large device.
Furthermore, in order to be commercially acceptable, such a freight container must be designed and built to internationally recognized standards such as those issued by the United Nations, the International Standards Organization (ISO) and the Association of American Railroads (AAR). These organizations promulgate standards for such containers relating to all facets of handling and carriage, including, among other things, strength, size, weight and materials used in the construction of the container. Applicable standards for containers such as the one disclosed herein include the ISO 1496/IV, AAR M-930, the United Nations' Council for Safe Containers (CSC) and Customs/TIR.
In order to withstand the testing dictated by the above standards to simulate actual operation of the container, such containers require additional support. Many containers known in the prior art use internal stiffener rings and similar structural support members. However, these designs create internal cavities or pockets which can trap product and which reduce the internal size of the container. Other designs use an internal frame for additional support. However, an internal frame reduces the internal volume in the container and thus makes the container less efficient. Therefore, it is preferred to use an external frame with such containers.
Shipping containers which are cylindrical in shape and which are commonly used with liquid product are unacceptable for use with dry product because the cylindrical shape does not allow a sufficient amount of cubic space within the frame.
Other currently available containers on the market use heavier, non-corrosion resistant materials such as carbon steel and are consequently much heavier, use a larger external frame, and have not been tested or certified to all of the standards as the current invention. Thus, those containers are not commercially economical for the regular transport of dry bulk commodities such as food products, pharmaceuticals and products sensitive to contamination. Furthermore, the designs currently available on the market do not conform to all the regulatory requirements set forth by the various governing bodies and are thus not acceptable for many applications.
Thus it has been widely recognized in the field that there is a need for an affordable, efficient dry bulk product transport container that satisfies the various testing requirements for certification by regulatory bodies and does not require tipping in order to unload product from the container.